| 词条 | Calcium hypochlorite |
| 释义 |
| Watchedfields = changed | verifiedrevid = 450959568 | Name = Calcium hypochlorite | ImageFile = Calcium hypochlorite.png | ImageSize = | ImageName = Calcium hypochlorite | OtherNames = Hypochlorous acid calcium salt Bleaching powder, Calcium oxychloride or chloride of lime | IUPACName = | SystematicName = | Section1 = {{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 22912 | InChI = 1S/Cacl.ClO/c;1-2/q+2;2*-1 | SMILES = Cl[O-].[Ca+2].Cl[O-] | InChIKey = ZKQDCIXGCQPQNV-UHFFFAOYAV | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/Ca.2ClO/c;2*1-2/q+2;2*-1 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = ZKQDCIXGCQPQNV-UHFFFAOYSA-N | CASNo = 7778-54-3 | CASNo_Ref = {{cascite|correct|CAS}} | EINECS = 231-908-7 | PubChem = 24504 | RTECS = NH3485000 | UNNumber = 1748 | Section2 = {{Chembox Properties | Formula = Ca(OCl)2 | MolarMass = 142.98 g/mol | Appearance = white/gray powder | Density = 2.35 g/cm3 (20 °C) | Solubility = 21 g/100 mL, reacts | SolubleOther = reacts in alcohol | MeltingPtC = 100 | MeltingPt_notes = | BoilingPtC = 175 | BoilingPt_notes = decomposes | Section3 = {{Chembox Hazards | ExternalSDS = ICSC 0638 | EUClass = {{Hazchem O}} (O) {{Hazchem C}} (C) {{Hazchem Xn}} (Xn) {{Hazchem N}} (N) | RPhrases = {{R8}}, {{R22}}, {{R31}}, {{R34}}, {{R50}} | SPhrases = {{S1/2}}, {{S26}}, {{S36/37/39}}, {{S45}}, {{S61}} | NFPA-H = 3 | NFPA-F = 0 | NFPA-R = 1 | NFPA-S = OX | FlashPt = Non-flammable | LD50 = 850 mg/kg (oral, rat) | Section4 = | Section5 = | Section6 = | Section8 = {{Chembox Related | OtherAnions = Calcium chloride | OtherCations = Sodium hypochlorite }} Calcium hypochlorite is an inorganic compound with formula {{calcium}}({{hypochlorite}})2. It is the main active ingredient of commercial products called bleaching powder, chlorine powder, or chlorinated lime, used for water treatment and as a bleaching agents.[1] This compound is relatively stable and has greater available chlorine than sodium hypochlorite (liquid bleach).[1] It is a white solid, although commercial samples appear yellow. It strongly smells of chlorine, owing to its slow decomposition in moist air. It is not highly soluble in hard water, and is more preferably used in soft to medium-hard water. It has two forms: dry (anhydrous); and hydrated (hydrous). UsesSanitationCalcium hypochlorite is commonly used to sanitize public swimming pools and disinfect drinking water. Generally the commercial substance is sold with a purity of a 65 to 73% with other chemicals present, such as calcium chloride and calcium carbonate, resulting from the manufacturing process. As a swimming pool chemical, it is blended with other chemicals less often than other forms of chlorine, due to dangerous reactions with some common pool chemicals. In solution, calcium hypochlorite could be used as a general purpose sanitizer,[2] but due to calcium residue, sodium hypochlorite (bleach) is usually preferred. Organic chemistryCalcium hypochlorite is a general oxidizing agent and therefore finds some use in organic chemistry.[3] For instance the compound is used to cleave glycols, α-hydroxy carboxylic acids and keto acids to yield fragmented aldehydes or carboxylic acids.[4] Calcium hypochlorite can also be used in the haloform reaction to manufacture chloroform.[5] ProductionCalcium hypochlorite is produced industrially by treating lime (Ca(OH)2) with chlorine gas. The reaction can be conducted in stages to give various compositions, each with different concentration of calcium hypochlorite, together with unconverted lime and calcium chloride. The full conversion is shown[6] 2 {{chem|Cl|2}} + 2 {{chem|Ca(OH)|2}} → {{chem|Ca(OCl)|2}} + {{chem|Ca|Cl|2}} + 2 {{chem|H|2|O}}Bleaching powder is made with slightly moist slaked lime. It is not a simple mixture of calcium hypochlorite, calcium chloride, and calcium hydroxide. Instead, it is a mixture consisting principally of calcium hypochlorite Ca(OCl)2, dibasic calcium hypochlorite, Ca3(OCl)2(OH)4, and dibasic calcium chloride, Ca3Cl2(OH)4.[7] PropertiesA calcium hypochlorite solution is basic. This basicity is due to the hydrolysis performed by the hypochlorite ion, as hypochlorous acid is weak, but calcium hydroxide is a strong base. As a result, the hypochlorite ion is a strong conjugate base, and the calcium ion is a weak conjugate acid: {{chem|ClO|-}} + H2O → HClO + {{chem|OH|-}} Similarly, calcium hypochlorite reacts with hydrochloric acid to form calcium chloride, water and chlorine: Ca(OCl)2 + 4 HCl → CaCl2 + 2 H2O + 2 Cl2 SafetyCalcium hypochlorite is stored dry and cold, away from any organic material and metals. The hydrated form is safer to handle. References1. ^{{cite web|author1=Gerald F. Connell|title=KEY OPERATING STRATEGIES FOR CHLORINE DISINFECTION OPERATING SYSTEMS|url=http://www.environmental-expert.com/Files%5C5306%5Carticles%5C13866%5C500.pdf|accessdate=19 October 2014}} 2. ^{{cite techreport|institution=Mannsvile Chemical Products |date=1987 |title=Chemical Products Synopsis: Calcium Hypochlorite |location=Asbuiy Park, NJ}} 3. ^{{cite journal|last1=Nwaukwa|first1=Stephen|last2=Keehn|first2=Philip|title=The oxidation of aldehydes to acids with calcium hypochlorite [Ca(OCl)2]|journal=Tetrahedron Letters|date=1982|volume=23|issue=31|pages=3131-3134|doi=10.1016/S0040-4039(00)88577-9}} 4. ^{{cite journal|last1=Nwaukwa|first1=Stephen|last2=Keehn|first2=Philip|title=Oxidative cleavage of α-diols, α-diones, α-hydroxy-ketones and α-hydroxy- and α-keto acids with calcium hypochlorite [Ca(OCl)2]|journal=Tetrahedron Letters|date=1982|volume=23|issue=31|pages=3135-3138|doi=10.1016/S0040-4039(00)88578-0}} 5. ^{{cite book|last1=Cohen|first1=Julius|title=Practical Organic Chemistry for Advanced Students|date=1900|publisher=Macmillan & Co.|location=Newyork|page=63|url=https://books.google.com/books?id=0xRIAAAAIAAJ&printsec=frontcover&source=gbs_atb#v=onepage&q&f=false}} 6. ^1 {{cite encyclopedia|last1=Vogt|first1=H.|last2=Balej|first2=J|last3=Bennett|first3=J. E.|last4=Wintzer|first4=P.|last5=Sheikh|first5=S. A.|last6=Gallone|first6=P.|last7=Vasudevan|first7=S.|last8=Pelin|first8=K.|year=2010|title=Chlorine Oxides and Chlorine Oxygen Acids|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry|publisher=Wiley-VCH|doi=10.1002/14356007.a06_483.pub2}} 7. ^W.L Smith, Inorganic bleaches, Production of Hypochlorite in Handbook of Detergents,Part F, (2009) Ed. U Zoller and Paul Sosis, CRCPress, {{ISBN|978-0-8247-0349-3}} External links
5 : Antiseptics|Bleaches|Hypochlorites|Calcium compounds|Oxidizing agents |
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